Advances in hearing preservation in cochlear implant surgery

Area of Science:

• Otolaryngology
• Neurosurgery
• Biomedical Engineering

Background:

• Advancements in cochlear implant (CI) surgery and electrode design facilitate residual acoustic hearing preservation.
• Preserving low-frequency hearing enhances electroacoustic stimulation (EAS), improving CI user performance in challenging auditory environments like music and speech-in-noise.
• Despite high success rates, predicting postoperative acoustic hearing outcomes remains challenging.

Purpose of the Study:

• To review current strategies and emerging innovations for hearing preservation in cochlear implantation.
• To discuss the impact of electrode design and surgical techniques on preserving residual acoustic hearing.
• To explore the pathophysiology of hearing loss after cochlear implantation and potential future solutions.

Main Methods:

• Review of literature on cochlear implant surgical approaches, electrode designs, and hearing preservation outcomes.
• Analysis of electrocochleography data for monitoring cochlear function during and after electrode insertion.
• Investigation into emerging technologies such as robotic-assisted insertion and drug-eluting implants.

Main Results:

• Thin, flexible, lateral wall electrode arrays are favored for hearing preservation.
• Both shortened and thin lateral wall arrays demonstrate success, though optimal implant selection is under investigation.
• Electrocochleography aids in monitoring cochlear function, and emerging innovations show promise in reducing trauma and improving hearing preservation.

Conclusions:

• Soft surgical techniques and trauma-minimizing electrode arrays enable hearing preservation in many CI patients.
• A subset of patients experience delayed partial to total acoustic hearing loss despite preserved apical hair cell function.
• Robotic-assisted insertion and dexamethasone-eluting implants represent promising future directions for enhanced hearing preservation.